This invention relates to apparatus for detecting objects of interest and is particularly, though not exclusively, applicable to radar systems for detecting moving targets and for indicating their range.
In the use of radar systems such as referred to above, situations often arise when there is no target, to which the radar is responsive, within the range of the system. It is therefore desirable for the operator to have some facility by which he can check that the radar is functioning correctly and will detect targets at any range within the limits of the system.